Sparking mechanism for internal-combustion engines.



In M m 3 0 e D d e t n e a P L L A C c M M H" 5 2 1 7 8 6 0 N SPABKINGMECHANISM FOR INTERNAL COMBUSTION ENGINES.

(Application filed Dec. 22, 1900.)

(No Model.)

' NITED STATES PATNT rricn.

PITTSBURGH GAS ENGINE COMPANY,

OF PITTSBURG, PENNSYL- VANIA, A CORPORATION OF PENNSYLVANIA.

SPAR KING MECHANISM FOR INTERNAL-COMBUSTION ENGINES.

SPECIFICATION forming part of Letters Patent No. 687,925, dated December3, I901.

Application filed December 22, 1900. Serial No. 40,813. (No model.)

To all whom it may concern:

Be it known that I, HARRY M. MOOALL, a citizen of the United States,residing at Pittsburg, in the county of Allegheny, State ofPennsylvania, have invented certain new and useful Improvements inSparking Mechanism for Internal-Combustion Engines; and I do herebydeclare the following to be a full, clear, and exact description of thesame, reference being had to the accompanying drawings, forming a partof this specification, and to the letters of reference marked thereon.

This invention relates to improvements in devices for igniting theexplosive mixture in internal combustion engines, the object of theinvention being to provide a simple, compact, highly efiicient, anddurable mechanism foroperating the sparking contacts between which theelectric spark is formed to ignite the explosive mixture, a furtherobject of the invention being to provide a means whereby the startingand control of the engine may be effected through the automaticadjustment of the contact-controlling mechanism, so as to create thespark when the piston is at different points in its path of travel.

To these ends the invention consists in certain novel'detailsofconstruction and combinations and arrangements of parts, all as willbe now described, and pointed out particularly in theappended claims.

In the accompanying drawings, Figure l is a perspective View of asparking mechanism with the contacts and operating devices shown intheir proper relative positions, but omitting the supporting-frame savefor the bearings for the operating-shaft. Fig. 2 is a detail view of thesparker-cam and its governor, showing the relative positions of theparts in dotted lines when the governorlever is thrown outward bycentrifugal force due to the speed of the engine. Fig. 3 is a detailface view of the sparking contacts at the inner end of the sparker-plug.Fig. 4 is a similar view, looking at the opposite end of thesparkerplug, with the cap of the spring-box removed, the parts in thisview being shown in full and dotted lines at opposite extremes of theirmovement. Fig. 5 is a detail elevation illustrating the action of thesparkercam when the engine is turned backwardly.

Like letters of reference in the several figures indicate the sameparts.

In' said drawings the letter A indicates a shaft which is adapted to berotated from the drive-shaft of the engine in any suitable or ordinarymanner and at a speed in proportion to the speed of the engine-shaft.

B indicates a sparker-plug which is adapted to be inserted through thewalls of the cylinder or explosion-chamber, as the case may be. The plugB carries a fixed contact 0, suitably insulated therefrom, with means,such as a binding-post c, atthe outer end for the attachment of one wireof the sparking circuit and at the inner end acontact-surface c, withwhich a movable contact is adapted to cooperate. In the form of deviceillustrated the movable contact D is mounted on an arm cl of a shaft D,journaled in the plug B and adapted to be oscillated by means of aconnection at its outer end extending down into position to be moved bya cam carried by the shaft A. The cam just referred to is lettered E inthe accompanying drawings and is preferably mounted loosely on the shaftA, so as to be capable of a limited independent oscillatory movement,such movement being controlled by a weighted governor-lever F, journaledin a suitable collar or carrier G,

mounted rigidly on the shaft A and in such position and relation to saidshaft A that by the rotation of said shaft it may be thrown outwardlyagainst the tension of a spring F to move the cam with relation to theshaft so as to advance the cam projection of the cam more or less, asthe case may be. The connection between the governor-lever and the camis preferably formed by an arm Won the shaft of the governor-lever,which arm takes into a slot or recess F in the cam E. The cam projectionE of the cam E is adapted to pass beneath the lower end of a rod H,extending upwardly through a movable guide I and connected at its upperend by a pivotal connectionwith the casing K of a spring-box, which isloosely journaled on the shaft of the movable contact. Said shaft, asshown in.

Fig. 4, is provided with an arm L, and the spring-box is provided with aprojection L, adapted when they contact and the rod I'I moves downwardlyto separate the sparking contacts; but when moved in the oppositedirection the said contacts are brought together through the medium of aspring M, mounted in the spring-box and tending at all times to hold theprojections L and L together, so as to move in unison.

In operation as the shaft A rotates the rod II will be elevated, puttingthe spring M under tension and bringing the sparking contacts together;but as the cam projection E moves away from beneath the rod H the springM will assert itself, driving said rod I-I downwardly quickly, and whenthe projections L and L come together the sparking contacts areseparated with a snapping action, which causes the spark to bridge thegap between the contacts in a manner well understood by engineers andelectricians skilled in this art. The action of the spring in thespring-box is to separate the contacts by a blow rather than by a slowmovement. Thus the spark is created at exactly the instant when the rodII is descending, and by varying the time when said rod shall descend,as by advancing or retarding the action of the cam projection withrelation to its shaft, the time of explosion with relation to theposition of the piston may be regulated. A buffer S may be inserted inthe cam to arrest the rod 11. In order to permit the backward rotationof the d rive-shaft, the cam projection E is sharpened at its highestpoint or side and the rod H is rounded at its lower end, whereby if saidshaft be rotated backwardly, as is frequently the case when the engineis being stopped, the said cam projection will contact with one side ofthe rod H and move the same laterally or longitudinally of the shaft A,such movement being permitted by forming the bearingI as part of acollar or sleeve I,surroundingthe shaft A,and providing a spring I forholding the bearing I in its normal position. Obviously other means maybe employed for holding the rod H in its normal position which willpermit said rod to move transversely when the engine is rotatedrearwardly, but will cause it to ride up on the cam projection wheneverthe engine is running and it is desired to create a spark for ignitingthe charge.

As is well understood, in the manipulation of gas-engines when runningat full speed or under load the explosion or spark for creating theexplosion takes place at or slightly before the crank of the engine ison its center or the piston at the extreme of its backward movement.Because of this fact difficulty has been experienced in starting theengine, for inmoving the piston slowly by hand the explosion is liableto take place'before the crank passes its center, and hence the enginemay be started reversely. For this reason the adjustment of the presentdevice is made to create the spark when the governor-lever is at itsinner position after the crank has passed its center and the piston hasbegun its forward movement. Thus the engineer may start the engine asslowly as desired, and the explosion will take place at the proper timeto drive the piston forwardly and the crank-shaftin the properdirection. In order now to bring the sparking time into proper relationto the piston and crank-shaft movement, the speed of the engine willswing the governor-lever outwardly and correspondingly move theprojection E of the cam rearwardly with relation to its shaft. It ispreferred that the adjustment should also be made so that thegovernor-lever will be swung outwardly to its limit as soon as areasonable speed is acquired bythe engine and will be held in itsoutward position by centrifugal force during the time the engine isrunning. \Vith this arrangement it will therefore be seen that no handmanipulation of either the sparker-cam or of the electric circuits isnecessary in starting the engine, but, on the contrary, the adjustmentis all automatically made both for starting and for securing the'highestefficiency while the engine is running.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. In a sparking mechanism for gas-engines the combination with adrive-shaft adapted to be operated from the engine-shaft, a cam mountedthereon and having a cam projection sharpened at its abrupt side, of asparker operating rod having its lower end which con= tacts with saidcam projection, mounted in a spring-pressed transversely-movable bearingwhereby when the shaft is turned reversely said rod will be displacedtransversely without operating the sparking contact; substantially asdescribed.

2. In a sparking mechanism for gas-engines the combination with adrive-shaft adapted to be driven from the engine-shaft and a cam mountedthereon having a cam projection sharpened at its abrupt side, of asparker-operating rod adapted to cooperate with said cam projection, abearing for the end of said sparker-rod having a collar surrounding thedrive-shaft and a spring for holding said collar and bearing inposition, whereby when the drive-shaft is rotated reversely said rod andbearing will be displaced transversely without operating the sparkingcontact; substantially as described.

In a sparking mechanism for gas-engines, the combination with the plugadapted to be screwed into the cylinder and havinga fixed contact at theinner end, a shaft journaled in said plug and having the arm at theinner end with a movable contact thereon adapted to cooperate with thefixed contact, and an operating stop-arm on the outer end of said shaft,of a casing journaled loosely on the shaft and inclosing theoperating-arm, a projection on the inner side of the casing adapted tocontact with said stop arm, a

ment, of a cam journaled on the cam-shaft and having a cam projectionand slot or recess, an arm on the governor-lever shaft entering saidrecess to advance the cam with relation to the shaft as thegovernor-lever swings outwardly and a sparking contact controlled ,bythe cam; substantially as described.

HARRY M. MCCALL.

Witnesses:

ALEXANDER S. STEUART, THOMAS DURANT.

